JP2006182879A - Polycarbonate-based resin film, material for optical recording medium given by using the same, and material for liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polycarbonate-based resin film having excellent slipperiness, without being deteriorated in optical characteristics, such as total light transmittance, haze, and retardation, to provide a material for an optical recording medium given by using the film, and to provide a material for a liquid crystal display. <P>SOLUTION: This polycarbonate-based resin film is formed out of a polycarbonate-based resin which contains beads made of a resin in an amount of 0.01-2 wt%, wherein a particle diameter of the beads is 0.1-5 μm and a difference of a refractive index of the beads from that of the polycarbonate-based resin is not more than 0.05. The material for the optical recording medium and the material for the liquid crystal display are provided by using the film, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polycarbonate resin film, an optical recording medium material using the same, and a liquid crystal display material.

Various recording plastics such as optical discs and liquid crystal display displays such as polycarbonate resins, thermoplastic norbornene resins, acrylic resins, polyester resins, epoxy resins, polyethersulfone resins, polyarylate resins, etc. These plastics are required to have characteristics such as transparency, heat resistance, surface smoothness, dimensional stability, and solvent resistance.
Among these plastics, polycarbonate resins having excellent properties such as transparency and workability are often used for optical recording medium materials and liquid crystal display materials.

  The development of next-generation optical discs capable of recording high-capacity high-definition broadcasts is being promoted with recent optical recording media. The next-generation optical disc is the same size as CD (compact disc) and DVD (digital versatile disc), but the layer structure is different, and the recording layer is transferred onto a 1.1mm injection-molded substrate to protect it. As a layer structure, an optical film of about 0.1 mm is attached.

  On the other hand, the liquid crystal display has features such as light weight and thinness, and is used for various applications including a display for a television and a personal computer. With the expansion of applications and the advancement of content, there is a growing need for large size, high definition and high viewing angle. In order to meet this need, development of films having high functions such as low retardation and high transparency has been underway.

  Next-generation optical discs and liquid crystal display displays are being used with films that have various functions, but these optical films are required to have high surface smoothness and have a very high coefficient of static friction. There are drawbacks. Patent Document 1 discloses a method for improving the coefficient of static friction by incorporating synthetic silica in a polycarbonate resin. However, since the refractive index of synthetic silica is significantly different from that of polycarbonate resin, internal scattering increases and haze deteriorates. As a result, when used as a material for an optical recording medium, there is a problem that a laser beam used for recording / reproducing is scattered and a recording / reproducing error occurs. Patent Document 2 uses cross-linked polystyrene beads having a refractive index difference of 0.05 or less from that of polycarbonate resin. However, since it contains a large amount of UV absorber, it records and reproduces signals from optical recording media. It does not transmit blue laser light of about 400 nm and cannot be used. Accordingly, there is a demand for a polycarbonate resin film that is excellent in transparency and haze and has good slipperiness.

JP 62-116655 A JP-A-10-279788

  The present invention provides a polycarbonate-based resin film that secures optical properties such as total light transmittance, haze, and retardation of the film, and further improves the slipperiness of the film, and an optical recording medium material and a liquid crystal display material comprising the same. That is.

The present invention
(1) A polycarbonate containing 0.01 to 2% by weight of resin beads having a particle size of 0.1 to 5 μm and a difference in refractive index from the polycarbonate resin of 0.05 or less. A polycarbonate-based resin film, which is molded from a resin-based resin composition,
(2) The coefficient of static friction of the polycarbonate resin film is 85% or more, the haze is 0.5% or less, the in-plane retardation is 15 nm or less, and measured by making the polycarbonate resin films face each other. Is a polycarbonate-based resin film described in (1), which is 1.5 or less,
(3) A material for an optical recording medium formed by using the polycarbonate resin film according to (1) or (2),
(4) A liquid crystal display material using the polycarbonate resin film according to (1) or (2),
It is.

  According to the present invention, it is possible to supply a film excellent in slipperiness without impairing optical properties such as light transmittance, haze, and retardation. Moreover, since it is excellent in slipperiness, when it is set as a laminated body, it is not necessary to bond the protective film for protecting the surface for blocking prevention.

    In the present invention, the polycarbonate-based resin to be used is not particularly limited, but it is desirable to use a polycarbonate-based resin having a glass transition temperature exceeding 140 ° C. for use in optical recording materials and display applications. Polycarbonate resin is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted or a transesterification method in which a dihydroxy dianneal compound is reacted with a carbonic ester such as diphenyl carbonate. Examples of such materials include, but are not limited to, those produced from bisphenol A.

  Examples of the resin beads include, but are not limited to, cross-linked polystyrene beads and acrylic resin beads. The amount of resin beads added is required to be 0.01 to 2%, preferably 0.1 to 0.5%. If the addition amount is less than 0.01%, even if the particle size is increased, the slipping property is inferior and secondary processing becomes difficult. When the addition amount exceeds 5%, the light transmittance and haze are inferior, and it becomes difficult to use them for optical recording medium materials and liquid crystal display materials.

  The particle size of the resin beads needs to be 0.1 to 5 μm or less, but is preferably in the range of 0.3 to 1 μm. If the particle size is less than 0.1 μm, the slipping property is inferior, and if it exceeds 5 μm, the light transmittance and haze are inferior, and the laser beam used for recording / reproducing of the optical recording medium is inhibited, making it difficult to use. The shape of the resin beads is preferably spherical, but is not limited thereto.

  The difference in refractive index between the resin beads and the polycarbonate resin is preferably 0.05 or less. The refractive index of the polycarbonate resin is 1.58, and if the difference between the refractive index of the polycarbonate resin and the polycarbonate resin exceeds 0.05, light is scattered in the polycarbonate resin film, resulting in poor transparency and haze. The laser beam used for recording / reproduction of the recording medium is obstructed and cannot be used.

  The method of forming a film from the polycarbonate resin containing the resin beads is not limited as long as optical properties such as light transmittance and retardation are not deteriorated. For example, it may be processed into a film by a melt extrusion method using a T die or a coat hanger die, and a solution in which a polycarbonate resin is dissolved in a solvent such as methylene chloride to form a film on a support such as a casting belt You may process into a film form by the casting method. The thickness of the polycarbonate resin film is preferably 10 μm to 400 μm, but is not limited thereto.

  The total light transmittance of the polycarbonate resin film used for the optical recording medium material and the liquid crystal display material needs to be 85% or more, and desirably 90% or more. Further, haze is required to be 0.5% or less, and desirably 0.1% or less. If the total light transmittance is 85% or less and the haze is 0.5% or more, the laser beam used for recording / reproducing on the optical recording medium is hindered.

  The in-plane retardation variation of the polycarbonate resin film indicates the variation in the degree of molecular orientation of the resin, and when the degree of molecular orientation is large, for example, when the plane birefringence exceeds 15 nm, linearly polarized light is applied to the film. When irradiated, a deviation occurs in the polarization state of the light transmitted through the film, and the linearly polarized light becomes elliptically polarized light. As a result, when a sheet having a high degree of molecular orientation is used as the optical recording medium material, the recording layer cannot be focused, and a recording / reproducing error occurs. In addition, when it is used for liquid crystal display materials such as STN type and TN type, partial leakage of light due to elliptically polarized light occurs, so it cannot be used for these materials.

  The static friction coefficient measured by making the polycarbonate resin films relative to each other needs to be 1.5 or less, preferably 1.0 or less. When the static friction coefficient exceeds 1.5, the slipperiness is poor and winding becomes difficult, and wrinkles such as wrinkles are generated during winding. Further, the polycarbonate resin films are brought into close contact with each other due to the blocking phenomenon, and unevenness called uneven contact occurs on the surface. Since wrinkles and uneven adhesion hinder the flatness of the polycarbonate resin film, when used as a material for an optical recording medium, the laser beam cannot be focused on the recording layer, and a recording / reproducing error occurs. When it is used for a liquid crystal display material, wrinkles and uneven adhesion are uneven in display color, and cannot be used.

  The polycarbonate-based resin film thus obtained is necessary for secondary processing in addition to the excellent properties inherent in the resin such as transparency and processability required for optical recording medium materials and liquid crystal display materials. The film has excellent slipperiness.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples.
<< Examples 1-4 and Comparative Examples 1-4 >>
A predetermined amount of beads made of a predetermined resin is added to a polycarbonate-based resin, melt-extruded with a coat hanger die having a width of 850 mm, sent to a cooling roll, cooled and solidified, and a polycarbonate-based resin having a sheet width of 660 mm and a sheet thickness of 100 μm. A film was prepared. Examples 1 to 4 and Comparative Examples 1 to 4 were prepared by the method described above. Table 1 shows the amount of resin beads added and the physical properties of the obtained film.

The polycarbonate resin and resin beads used the following.
* Polycarbonate resin: Caliber 301-15 manufactured by Sumitomo Dow Co., Ltd., refractive index 1.58
* Resin beads:
(A) SX8742 (C) manufactured by JSR Corporation, cross-linked polystyrene resin, particle size 0.5 μm, refractive index 1.59
(B) SX8703 (C) manufactured by JSR Corporation, cross-linked acrylic resin, particle size 2 μm, refractive index 1.49
(C) SX60H manufactured by Soken Chemical Co., Ltd., cross-linked polystyrene resin, particle size 0.6 μm, refractive index 1.59
(D) SBX-8 manufactured by Sekisui Plastics Co., Ltd., cross-linked polystyrene resin, particle size 8 μm, refractive index 1.59
(E) MBX-15 manufactured by Sekisui Plastics Co., Ltd., cross-linked acrylic resin, particle size 15 μm, refractive index 1.49

Further, the optical properties of the film of the present invention were measured by the following method and are shown in Table 1.
* Static friction coefficient The static friction coefficient was measured according to JIS K-7125. The static friction coefficient was calculated by the following formula.
Static friction coefficient = static friction force / load * total light transmittance / haze Based on JIS K-7361, a turbidimeter made by Nippon Denshoku (NDH2000) was used.
* In-plane retardation of polycarbonate resin film Using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Instruments Co., Ltd., the planar phase difference and orientation angle were measured by a parallel Nicol rotation method at a wavelength of 590 nm. The orientation angle indicates the inclination in the major axis direction of the refractive index ellipsoid, and the inclination is based on the width direction (0 °). The major axis direction of the refractive index ellipsoid is taken as the optical principal axis. The sheet sample was sampled and measured at a pitch of 50 mm in the width direction. A value obtained by dividing the optical retardation value Re by the thickness d is the planar birefringence. The calculation formula is ΔNxy = Re / d.

  According to the present invention, an optical polycarbonate resin film excellent in slipperiness can be supplied without impairing optical properties such as total light transmittance and haze. An optical recording material and a liquid crystal display material using the film are useful.

Claims (4)

  Polycarbonate resin composition containing 0.01 to 2 wt% of resin beads having a particle size of 0.1 to 5 μm and a refractive index difference of 0.05 or less with respect to the polycarbonate resin A polycarbonate-based resin film characterized by being molded from a product.   The polycarbonate resin film has a total light transmittance of 85% or more, a haze of 0.5% or less, an in-plane retardation of 15 nm or less, and a coefficient of static friction measured by making the polycarbonate resin films face each other. The polycarbonate resin film according to claim 1, which is 5 or less.   An optical recording medium material using the polycarbonate resin film according to claim 1.   A liquid crystal display material using the polycarbonate resin film according to claim 1.